L322 low idle

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Land Ho!

New Member
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180
Location
Surrey
Hi guys. Does anyone know what might cause an L322 V8 to idle low? About 350 rpm. Anything i can check myself?
I did a search but couldn't find any info on low idle.
Ta.
 
If your driving involves a lot of idling I wouldn't drive it like this, camshaft wear at such low RPM will be significantly accelerated.
 
Breather pipes blocked or leaking or a failed idle valve get the ecu tested

Hi Vouge.
I do remember seeing some sort of breather pipe uder my car down the side of the gearbox (but not part of the gearbox) that has been melted and mangled a bit. Is that where the breather pipe would be? I'll look into it though so thanks.
I had a full diagnostics check at LR the other week and they said all ECU's were fine.
I just replaced a CAT and o2 sensors....i was hoping that would solve it.
 
If your driving involves a lot of idling I wouldn't drive it like this, camshaft wear at such low RPM will be significantly accelerated.

Oh god don't say that! It's had a low since i bought it about 9 months ago.
I didn't realise you could wear a metal part down more by making it move slower? :confused: :D
 
Oh god don't say that! It's had a low since i bought it about 9 months ago.
I didn't realise you could wear a metal part down more by making it move slower? :confused: :D

Camshafts lobes - like big end journals - are lubricated by the hydrodynamic wedge principle, the relative movement of the two surfaces forms a wedge of oil which the cam-lobe "surfs" on, when the nose of the camshaft lobe reaches the follower, this wedge starts to break down as it spills off the nose of the lobe, also if the lobe is moving too slowly the wedge isn't properly formed, at low RPM the window of opportunity where the spillage and therefore breakdown of the wedge will increase possibly leading to the nose of the cam being dragged slowly over the follower instead of on a wedge of oil. This is why a slower moving lobe will increase wear. The removal of zinc from modern oil (to protect catalytic converters) doesn't exactly help matters either as this was the last line of defence against metal to metal contact, and there's nothing remotely as good as it to provide the same characteristic.

Depending on clearances and amount of wear, the big-ends may suffer too, oil pressure and flow isn't exactly generous at idle with Rover V8s, at very low rpm oil spillage from the big-ends may outstrip supply, the reduced rotational speed will also inhibit the formation of the hydrodynamic wedge as described above encouraging metal to metal contact.
 
Camshafts lobes - like big end journals - are lubricated by the hydrodynamic wedge principle, the relative movement of the two surfaces forms a wedge of oil which the cam-lobe "surfs" on, when the nose of the camshaft lobe reaches the follower, this wedge starts to break down as it spills off the nose of the lobe, also if the lobe is moving too slowly the wedge isn't properly formed, at low RPM the window of opportunity where the spillage and therefore breakdown of the wedge will increase possibly leading to the nose of the cam being dragged slowly over the follower instead of on a wedge of oil. This is why a slower moving lobe will increase wear. The removal of zinc from modern oil (to protect catalytic converters) doesn't exactly help matters either as this was the last line of defence against metal to metal contact, and there's nothing remotely as good as it to provide the same characteristic.

Depending on clearances and amount of wear, the big-ends may suffer too, oil pressure and flow isn't exactly generous at idle with Rover V8s, at very low rpm oil spillage from the big-ends may outstrip supply, the reduced rotational speed will also inhibit the formation of the hydrodynamic wedge as described above encouraging metal to metal contact.

You learn something everyday! Thanks for that mate.

Oh by the way....it's snowing here in surrey!! woo hoo!! Tow ropes at the ready! :)
 
All the ECU's are fine according to LR.
Where are the breather pipes so i can check them? Cheers guys.
at the rear of the engine , remove the cabin filter houseing - 2 13mm nuts and slide out the remove the engine cover , then you will have to mount the slam panel and lie on top of the engine put some old coats/jackets on the engine to make it more comfortable , then look at the rear of the inlet manifold you will see 2 large vacuum pipes running to the pcv valve check these as they go all gummy and soft and even flat and holed .if they are they will need to be changed along with the pcv valve and the 2 smaller vacuum hoses , it would be a false economy not to change them all


[ame=http://www.youtube.com/watch?v=cs3Y2JKAM70&feature=player_embedded#]Range Rover MKIII - Replace PCV Valve P1 - YouTube[/ame]!


[ame="http://www.youtube.com/watch?v=G8cI6KeNpfo&feature=player_embedded"]Range Rover MKIII - Replace PCV Valve P2 - YouTube[/ame]
 
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Oh THOSE breather pipes! lol. Sorry i was thinking of something under the car. I checked those when i bought the car because i had heard about the design fault on the PVCThey are the same videos i saw ages ago too :)
Thanks anyway mate.
 
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